Time lines recording apparatus



Dec. 26, 1939. A. B. BRYAN 2,184,953

TIME LINES RECORDING APPARATUS Filed May 13, 1936 2 Sheets-Sheet '1 Dec.26, 1939. A. B. BRYAN 2,184,953

TIME LINES RECORDING APPARATUS File d May 13, 1936 2 Sheets-Sheet 2Patented Dec. 26, 1939 a rim mans aacoanme APP ros Andrew B. Bryan,Tulsa, Okla, or to Standard Oil Development company, a corporation ofDelaware Application May 13, 1936, Serial No. 79,470

1 Claim.

This invention relates to improvements in a device for obtaining-timelines on a record.

The invention will be fully understood from the following descriptiontaken in connection with the accompanying drawings, in which latter-Fig. 1 is a side elevational viewof the device;

Fig.2 is a top plan view of the device;

Fig. 3 is a side elevational view of the tuning fork assembly lookingalong the line III-HI of Fig. 1;

Fig. 4 is a side elevational view of the tuning fork assemblylookingalong the line IV-IV of Fig. 1, showing the tuning fork invibration, and

Fig. 5 is a front elevational view of a record showing the time linesthereon.

Referring particularly to the drawings, reference numeral l designates atuning fork. A vibratory reed or any other suitable vibratory sys-' temof given frequency can be used in place ofthe tuning fork and some ofthe advantages of the invention will be retained. The tuning fork l iselectrically started by means of an electromagnet 3. Leads 4 and 5 ofthe electro-magnet are connected to a suitable driving mechanismincluding a battery 6. The circuit through the leads 4 and 5 iscompleted by means of a switch I. In theembodiment illustrated theelectromagnet 3 is disposed between the prongs or arms Y I 0 and II ofthe tuning fork. When the switch I of the circuit is closed, theelectro-magnet 3 operates to pull the prongs l0 and II together. Whentheswitch 1 is opened the prongs are thereupon immediately released topermit the prongs l0 and II to vibrate freely. The switch I is operatedby a manual control designated l5, which serves to close the switch Iand then open it again immediately, and also to start the driv ingmeans, not shown, which rotates the recording drum 3| and moves thesensitive film 30. Free vibration of the tuning fork is thus attained,since the fork is acted upon by no external forces during the time thatthe film is moving. 3

Flashes of light are caused to be created at. intervals proportional tothe vibrations of the taxiing fork, as follows; The prong ll] of. thetuning fork is provided with a shutter I! which is secured to the end ofthe prong and extends-toward the prong ll of the tuning fork andterminates in slightly spaced relation to the prong ll, soas not tointerfere with vibration of the prong II. A shutter I8 is secured to theprong II and extends" parallel with and in slightly spaced relation tothe shutter I! in overlapping able means (not shown).

relation with respect to the shutter II. The shutters i1 and I8 areprovided with slits 20 and M respectively, which are in alignment witheach other when the prongs of the tuning fork are in their restposition, as can be clearly seen in Fig. l. A source of light, such as alamp. 2%, is disposed on one side of the tuning fork in position todirect-a beam of light 26 through the slits 20 and 2! when they are intheir aligned w position. The beam of light 26 passes through the slits20 and 2! intermittently, creating flashes of light 21!. In one form. ofthe invention, the tuning fork i may have a cycle of 50 vibrations persecond. During the vibration of the fork 15 the slits 20 and 2! are inalignment every half cycle. Thus, light from the lamp 25 passes throughthe shutters at intervals of ,400 seconds.

The flashes of light 21 are recorded upon a recording device to createtime lines, as follows: In the embodiment illustrated, therecordingdevice includes a sensitive film 30 carried by a recording drum 3| anddriven in travel by any suit- The flashes of light 21 from the lamp 25are focused upon the film 30 as indicated at 32, by means of acylindrical lens 33. 25

A record formed by the flashes of light is il-. lustrated in Fig. 5,which shows dark time lines 36 across the film 30.

In utilizing the device, an electric current is caused to flow throughthe electro-magnet 3 for a sufficient length of' time only to start thetuning fork in vibration. At the same time, the film 30 is driven inmovement across the face of the drum 3|. The free vibrations ofthetuning fork result in the formation of intermittent flashes of lightwhich are recorded upon the travelling film. The film is driven at aconstant rate of speed.

By the construction described, a timing device is provided which isextremely simple in construction. The device is of particularapplication for use in placing time'lines upon a solemngraph recordobtained in making seismic explorations. In seismic explorations, it iscustomary to create a, source of seismic vibrations at a given shotpoint and to record the vibrations, such as those reflected from asubterranean earth stratum, by means of one or-more seismographs locatedat a receiving station spaced from the shot point. The free vibrationsof the tuning fork give time lines on the record for a sum-j cientlength of time to record seismic vibrations. Thelength of time necessaryto record the vibrations may be in practice, for example, one or twoseconds. During this interval of time the fork is acted upon by-noforces. Furthermore, 66,

there are no electrical circuits associated with the tuning fork duringits vibration to affect the frequency of vibrations of the tuning fork.The electric circuit connected to the electro-magnet 3 is open after theinitial excitation of the tuning fork. The eflect on the frequency ofthe decay'in amplitude of the vibrations of the tuning fork during thetime interval for which the records are run, is negligible. Thefrequency of the tuning fork is entirely stable, while the reading isbeing made. There are no associated electrical circuits connected to thetuning fork which would function to cause disturbances in the othercircuits of the seismograph apparatus.

Various changes and alternate arrangements may be made within the scopeof the appended claim, in which it is my intention to claim all noveltyinherent in the invention as broadly as the prior art permits.

I claim:

A device for obtaining time lines on a record for approximately 2seconds during the unsustained vibrations only of a tuning fork,comprising a tuning fork having a cycle of approximately 50 vibrationsper second, a shutter carried by each prong of the fork, the shuttersoverlapping and having aligned slits when in rest position, means forstarting the prongs in vibration to give unsustained vibrations only, alight sensitive film on one side of the shutters movable at a constantspeed transversely of the slits, a stationary point of light on anopposite side of the shutters whereby a gradually widening beam of lightpasses through the slits of the shutters when they are in alignment, anda cylindrical lens having its long axis parallel with the slits disposedbetween the shutters and film, and relatively close to the film to focusthe beam of light upon the film whereby successive time lines arerecorded on the film at intervals of about ,4 of a second.

ANDREW B. BRYAN,

